278 Account of a portable Apparatus 
a drop or two of ether posited here will expand in the air of the 
cylinder, and this mixed atmosphere will act with all the conse- 
quence of nitrous oxide. 
These provisions, for various reasons, are valuable auxiliaries 
in returning respiration. 
The victim of suspended animation is to be raised ina gently 
inclined position opposite to the operator, the nostrils are to be 
plugged up, and the plate of leather fixed on the mouth as nearly 
air tight by means of white of egg, &c. as possible, and 
this is kept in its position by means of a ribbon tied round the 
head. The operator over against the victim manages uniformly 
and equably the piston. The apparatus being adjusted in the 
manner described, the air is first withdrawn from the lungs and 
then ejected laterally; and the piston rod being drawn to the ex- 
tremity of the cylinder (if adult), the pure atmospheric air fills 
the instrument ; and the communication with the lungs being re- 
stored by turning the stop-cock parallel with the pipe, the ope- 
ration begins. About twenty plunges of the piston in the minute 
may be the proper number; it will not be necessary to change 
the included air until natwral respiration is restored, because, 
until, this does take place, the blood cannot eject its excess of 
carbon, the consequence of the circulation of that fluid; but when 
this is required, it is instantly accomplished in the manner. already 
described. 
It is cheering to me to be assured that this invention has met 
the most unequivocal testimony of approbation from several emi- 
nent physicians and surgeons, and is pagiesk of distinguished 
mechanical genius. 
It has been used with great success on some inferior animals, 
The internal cylinder, one foot long and three inches diameter, 
contains 84:82 cubic inches, and about half of this extent will 
suffice for ordinary respiration, agreeably to the following caleu-. 
Jation in Keill’s Anatomy: ‘* By the rise of the breast-bone in: 
man and the descent of the diaphragm, room is afforded for 42 
cubic inches of atmospheric air at every drawing in of the breath. 
A deeper inspiration will give room for more than twice this. 
quantity.” 
The following, deduced from the very interesting experiments 
of Messrs. Allen and Pepys on respiration, may aid in appreciat- 
ing the preceding observations. 
«1. The inspired air imparts none of its oxygen or nitrogen: 
to the blood. 
“2. The blood loses a principle, viz. carbon, which by its 
union with the oxygen of the inhaled air forms carbonic acid gas. 
«¢ 3. The watery vapour found in expired air is the serous 
discharge of the bronchial tubes, 
“4, The 
